1. Field of the Invention
The present invention concerns the discovery and use of 1,1,1-trisubstituted hydrazinium salts in vicarious nucleophilic substitution (VNS) reactions, which provide new and improved syntheses of DATB and TATB.
2. Description of the Problem and Related Art
Some explosives are more sensitive to shock and heat than others having a similar structure. Studies of explosives based on the benzene ring include, for example, 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), 1-monoamino-2,4,6-trinitrobenzene (MATB) (aka picramide), 1-3-diamino-2,4,6-trinitrobenzene (DATB) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Although these compounds have much in common, the shock initiation thresholds, that is, the shock pressure required to cause detonation in 50% of the tests, vary widely. Table 1 shows the pattern.
TABLE 1 ______________________________________ SHOCK INITIATION THRESHOLD OF EXPLOSIVES Compound Pressure (kilobars) ______________________________________ TNB 17 TNT 21 MATB 30 DATB 46 TATB 75 ______________________________________
While not wanting to be bound by theory, it appears that adding amino groups to a nitro-substituted benzene ring raises the initiation shock threshold. This pattern occurs, because as the networks of hydrogen bonds increase, the networks absorb energy from a shock front and reduce the amount of shock that goes to the ring itself. See W. Worthy in "Shock Sensitivity of Explosives Clarified", Chemical and Engineering News, p. 25, (Aug. 10, 1987) for further discussion.
It follows that DATB and TATB are highly desirable, insensitive explosives that are used primarily in specialty applications. Part of the reason that they are used in special as opposed to general explosive applications is high cost. They are too expensive to use in ordinary applications when other less expensive explosives can be used. One reason that TATB is expensive is that it is usually prepared from 1,3,5-trichlorobenzene which is expensive and is not generally available from domestic suppliers. The chloride byproduct (NH.sub.4 Cl) is difficult to remove completely and may cause compatibility problems in certain types of ordnance (cf. U.S. Pat. No. 4,032,377).
Alternative preparations were sought, and
T. M. Benziger, U.S. Pat. No. 4,032,377 discloses a preparation of TATB by nitration of 1,3,5-trichlorobenzene to 1,3,5-trichloro-2,4,6-trinitrobenzene followed by treatment with ammonia to produce TATB. This patent also discloses the use of water to separate the byproduct ammonium chloride.
D. G. Ott and T. M. Benziger, U.S. Pat. No. 4,952,733 and Journal Of Energetic Materials, vol. 5, pp. 343-354 (1987) disclose a preparation of TATB by nitration of 3,5-dichloroanisole to produce 3,5-dichloro-2,4,6-trinitroanisole which is chlorinated to give 1,3,5-trichloro-2,4,6-trinitrobenzene which is ammonolyzed to give TATB.
Additional art of interest includes, for example:
R. T. Atkins et al., in U.S. Pat. No. 4,248,798 disclose a new method for preparing pentanitroaniline (PNA) and triaminotrinitrobenzene (TATB) from TNT. TNT is first reduced using H.sub.2 S to 4-amino-2,6-dinitrotoluene then nitrated using nitric acid/sulfuric acid to pentanitroaniline followed by reaction with ammonia to produce the TATB.
M. Makosza et al., review and discuss "Vicarious Nucleophilic Substitution of Hydrogen", in Accounts of Chemical Research, vol. 20, pp. 282-9 (1987), and teach the substitution of polynitrobenzene structures with a number of non-nitrogen containing vicarious nucleophilic substitution reagents. No nitrogen-containing reagents are suggested.
A. R. Katritzky and K. S. Laurenzo, Journal of Organic Chemistry, vol. 51, pp. 5039-5040 (1986) disclose mono-amination of nitrobenzene and some substituted nitrobenzenes to give 4-nitroanilines by VNS reactions. The same authors, in the Journal of Organic Chemistry, vol. 53, pp. 3978-3982 (1988) disclose the use of a series of 4-(alkylamino)-1,2,4-triazoles to transfer the alkylamino group to the 4-position of nitrobenzene and 3-substituted nitrobenzenes by VNS.
T. Urbanski et al., Journal of Scientific and Industrial Research (India), vol. 37, p. 250-5 (1978), disclose the standard preparation and properties of several heat resistant explosives including DATB and TATB.
J. R. Holden et al., U.S. Naval Ordnance Laboratory, White Oak, Md., NAVORD Report 6299 (March 1959), disclose the properties of DATB.
S. K. Yasuda et al., in Journal of Chromatography, vol. 71, p. 484-86 (1972) discuss the separation and identification of 12 impurities of 1,3,5-triamino-2,4,6-trinitrotoluene by two dimensional thin-layer chromatography.
M. Makosza et al., Journal of Organic Chemistry, vol. 57, p. 4784-5 (1992), disclose the mono-amination of nitrobenzenes with sulfenamides via vicarious nucleophilic substitution of hydrogen.
W. P. Norris et al., "CL-14, A New Dense, Insensitive, High Explosive", Naval Weapons Center, China Lake, Calif., Report No. TP 6597 (Unclassified), May 1985, disclose the use of hydroxylamine to di-aminate 4,6-dinitrobenzofuroxan (DNBF) thereby producing 5,7-diamino-4,6-dinitrobenzofuroxan (CL-14).
R. T. Atkins et al., in the Journal of Organic Chemistry, vol. 51, pp. 3261-3266 (1986), disclose the synthesis of a number of polynitro compounds, including TATB. Pentanitroaniline is reacted with ammonia to produce TATB.
T. R. Gibbs et al., LASL Explosives Properties Data (University of California Press, Berkeley, Calif., 1980.
B. M. Dobratz, LLNL Explosives Handbook: Properties Of Chemical Explosives and Explosive Simulants, Lawrence Livermore National Laboratory, Livermore, Calif., UCRL-52997 (March 16, 1981 ).
German patent, Ger. Offen DE 3,612,238) teaches the use of TATB to prepare components of lyotropic liquid-crystal phases for use in display devices.
None of these references individually or collectively teach or suggest the present invention.
It is apparent from this description that there is a need for a new process that is milder and more environmentally benign to easily convert nitroaromatic compounds to DATB, TATB or mixtures thereof. The present invention provides such useful processes which avoid strong acids (H.sub.2 SO.sub.4, HNO.sub.3) at elevated temperatures (100.degree.-150.degree. C.) and the need for noxious materials such as ammonia, thionyl chloride and hydrogen sulfide. These processes are also environmentally benign.